1. Field of the Invention
The present invention relates to a method for replacing a process instrument in a processing apparatus used for processing a target object, such as a semiconductor wafer, and a storage medium that stores a program for replacement.
2. Description of the Related Art
In general, in the steps for manufacturing semiconductor devices or the like, a photolithography technique is utilized to form a resist pattern on the surface of a substrate to be processed (which will be referred to as a target object), such as a semiconductor wafer or LCD substrate. This photolithography technique includes a resist coating process for applying a resist liquid onto the surface of the target object; a light exposure process for subjecting the resist film thus formed to light exposure with a circuit pattern; and a developing process for supplying a developing solution onto the target object treated by the light exposure process. These processes are performed by use of a coating/developing apparatus.
In general, a coating/developing apparatus includes a carry-in section and a carry-out section for transferring target objects into and out of the apparatus; processing units for performing processes of various types, such as the resist coating process, light exposure process, and developing process, described above; and an interface section for transferring target objects between these areas. The interface section includes transfer means, such as a transfer arm, by which target objects are sequentially transferred from the carry-in section to selected ones of the processing units. Each of the processing units has a transfer port provided with a shutter, through which a target object is loaded into the processing unit. The target object thus loaded is subjected to a process, such as the coating process, in the processing unit. Thereafter, the processed target object is transferred by the transfer means to another processing unit or the carry-out section.
Each of the processing units has an opening provided with a cover door on the side (outer side) opposite to the transfer port provided with the shutter. Where a maintenance operation is performed on each of the processing units, the cover door of the opening is opened by an operator. When the cover door is opened, an interlock mechanism is activated to stop the entire operation of the coating/developing apparatus, thereby satisfying a safety standard.
For example, a coating unit includes a spin chuck located therein for holding a target object or substrate, and a process cup serving as a process instrument for surrounding the spin chuck and target object. A process liquid is supplied onto the surface of the substrate set in a state described above, while the substrate is being rotated. Currently, the process cup needs to be replaced twice a week. When the cover door of the coating unit is opened to perform this cup replacing operation in the middle of processes, the interlock mechanism is activated to stop the transfer means or transfer mechanism. In light of this, conventionally, the process cup replacing operation is performed after the light exposure process and developing process in processing units are finished and all the target objects are collected into a carrier.
However, while the interlock mechanism is in an activated state for maintenance of one of the processing units, the coating/developing apparatus is entirely stopped until the maintenance is finished. This means that the operation rate of the apparatus is decreased.
In light of this, there is proposed a substrate processing apparatus to improve the apparatus operation rate (for example, see Jpn. Pat. Appln. KOKAI Publication No. 2006-12912). According to this apparatus, an interlock mechanism is set disabled on the condition that the shutter of the transfer port of a processing unit is closed by an operator. This makes it possible to prevent the processing apparatus from being undesirably entirely stopped when the cover door is opened.
However, depending on the type of a processing unit, unsolved problems remain when an operator simply closes the shutter by a switching operation to set the interlock mechanism disabled.
For example, where a processing apparatus includes only one coating unit as a whole, a replacing operation of the process cup of this coating unit brings about a state where no usable coating unit is present in the apparatus. In this case, it is necessary to set takeoff suspension of the next lot and/or to stop the processing apparatus entirely. Further, even where a processing apparatus includes a plurality of coating units, the program needs to be modified to bypass the processing unit designated as a cup replacement target.
Further, where a cup replacing operation is performed on a coating unit, it is preferable that the process cup can be replaced immediately after the process in the coating unit is finished. However, the conventional technique is arranged such that an operator closes the shutter of the transfer port of an objective processing unit by a switching operation, without an automatic judgment as to whether the process in the processing unit is finished. In this case, the operator is required to make a judgment as to when the shutter should be closed while processes are sequentially performed. Accordingly, a time delay tends to be caused after the process in the processing unit is finished and before the shutter is closed and the cover door is opened.
Such a problem may be also caused in replacement or inspection of another process instrument that constitutes a processing unit, such as a nozzle or spin chuck, besides a process cup.